ARLINGTON –- The Rangers have cut the cord on struggling left-hander Drew Smyly and optioned pitcher Joe Palumbo to Triple-A Nashville. Right-hander Jesse Chavez is moving to the rotation with his first start scheduled for Tuesday against the Tigers.

The Rangers also announced on Thursday morning that left-handers Kyle Bird and Locke St. John have been called up from Triple-A. This is the fourth time Bird has been on the Rangers roster, but St. John -- a side-arming lefty similar to Alex Claudio -- will be making his Major League debut.

Smyly was acquired from the Cubs on Nov. 2 after missing two full seasons while recovering from Tommy John elbow reconstruction surgery. He was a front-line starter for the Tigers and Rays in 2012-16 with a career 3.74 ERA before needing surgery.

But he could never get back to his former level. Instead he was 1-5 with an 8.42 ERA in nine starts and four relief appearances, and the Rangers finally decided they had seen enough, designating him for assignment before Thursday's game against the Indians.

“It’s a tough situation,” manager Chris Woodward said. “He is coming off injury. I don’t think the expectations were overly high, but it just didn’t work out. He was fighting to figure things out. It was best for him and best for us to have him move on.”

The Rangers expected a longer look at Palumbo after calling him up from Double-A Frisco for his second Major League start. But he allowed seven runs in two-plus innings in a 10-4 loss to the Indians on Wednesday and the Rangers were concerned more struggles would hit his confidence. He still gets a semi-promotion as the Rangers are sending him to Nashville instead of Frisco.

“Joe is in a great spot,” general manager Jon Daniels said. “He is a big part of our future and is going to pitch big innings for us. It might be this year, but definitely down the line. When you take a step back and look at it, he is in a good spot as far as the big picture. We brought him here sooner than we planned, but this is a good learning lesson, something he can use to improve his game moving forward.”

Chavez was re-signed this winter as a reliever, but has 74 career Major League starts (449 appearances) in his 12-year career. The Rangers have used him in long relief lately -- he threw five innings and 59 pitches in relief of Palumbo on Wednesday night. He went three innings and 47 pitches in a start on Friday against the Reds. He is 2-1 with a 0.58 ERA and 0.94 WHIP in his last 21 outings since the beginning of May.

“He has done a great job for us,” Woodward said. “The fact that we were able to extend him out the last two times, he’ll be able to throw 75-80 pitches the next time out, which is nice. At least it won’t be a two-to-three-inning start. It will actually be a legitimate start. I love him in the bullpen, but we can use him in the rotation.”

St. John will be the ninth pitcher to make his Major League debut for the Rangers this season. That will be the most for the Rangers in one season prior to September callups in club history Three of those -- Bird, left-hander Brett Martin and right-hander Peter Fairbanks -– are on the big league roster.

St. John was a 32nd round pick for the Tigers in 2014 out of the University of South Alabama who was going nowhere in their system as a starter until 2017. That’s when he changed to a sidearm delivery and became an effective reliever. Claudio, the Rangers Pitcher of the Year in 2017, was one of the pitchers he studied on the Internet while making the transition.

The Rangers took St. John in the Minor League Rule 5 Draft in 2017 and he has been an impact reliever for them this season. He pitched in 22 games at Frisco with a 1.52 ERA and a 1.15 WHIP. He also had 42 strikeouts in 29 2/3 innings before being promoted to Nashville. He made four appearances for the Sounds before being called up.

“I got the call last night and didn’t sleep,” St. John said. “This has been a dream of mine since I was six years old. I was hoping this day would come. I just need to come here and get guys out.”

Bird has a 6.75 ERA in six games with the Rangers and 2.30 ERA in 13 games for Nashville.